Zemax Opticstudio User Manual-------- Direct

The PDF is massive. If you want to know about "Ghost Reflections," search the term. The manual's indexing is excellent, but a text search is faster.

To open the manual is to realize: no one can remember all of OpticStudio. But the manual remembers for you. Zemax Opticstudio User Manual--------

If you need the actual manual, it is available via the menu inside OpticStudio or from the Zemax (Ansys) support portal. The current version exceeds 4,000 pages across all modules. The PDF is massive